Omni-directional antenna mounted in circular radome

ABSTRACT

There is disclosed a method for manufacturing a television antenna, as well as a television antenna which is manufactured according to the preferred method. The television antenna of the preferred embodiment comprises a layer of flexible non-conductive material, such as mylar, on top of which is affixed a plurality of strips of flexible conductive material. Electrical leads are connected to the flexible strips of conductive material and the entire flexible structure is then placed on a rigid housing. In the preferred embodiment, the rigid housing comprises a circular non-conductive shell. The flexible layer of laminated conductive and non-conductive material is placed circumferentially around the interior of the circular shell, thereby forming an omnidirectional antenna which is completely impervious to corrosive elements.

United States Patent [1 1 Clavin et al.

[451 Aug. 21, 1973 OMNI-DIRECTIONAL ANTENNA MOUNTED IN CIRCULAR RADOME[73] Assignee: Vorta Systems, Inc., Round Lake, Ill.

[22] Filed: Mar. 7, 1972 [21] Appl. No.: 232,562

Primary Examiner-Eli Lieberman Attorney-Jack C. Berenzweig [5 7]ABSTRACT There is disclosed a method for manufacturing a televisionantenna, as well as a television antenna which is manufactured accordingto the preferred method. The television antenna of the preferredembodiment comprises a layer of flexible non-conductive material, suchas mylar, on top of which is affixed a plurality of strips of flexibleconductive material. Electrical leads are connected to the flexiblestrips of conductive material [52] U.S. Cl. 343/742, 343/872 and theentire flexible structure is then placed on a Int. Clhousing. In thepreferred nt, e [58] Field of Search 343/741, 742, 872, housingcomprises a circular nomconductive She". The 343/908 flexible layer oflaminated conductive and nonconductive material is placedcircumferentially around [56] References the interior of the circularshell, thereby forming an UNITED STATES PATENTS omni-directional antennawhich is completely impervi- 3,261,019 7/1966 Lundy 343/742 ous tocorrosive elements. 3,626,418 12/1971 Berryman (at al. 343 742 3,656,1604 1972 Burton 343/742 11 Chums, 6 Drawing Figures /Z 24 M 21 14 I 4OMNI-DIRECTIONAL ANTENNA MOUNTED IN CIRCULAR RADOME BACKGROUND OF THEINVENTION The present invention relates to antennas and moreparticularly, to an improved omni-directional antenna for use withtelevision receivers and/or FM receivers.

In the field of antennas, it has been the general practice to employdipole antennas. These dipole antennas have not proved entirelysatisfactory and subsequently, Yagi-type antenna arrays were developed.The Yagitype array usually employed an active or radiator element, incombination with one or more directors and- /or reflectors. The use ofthese several elements widen the frequency response of the antenna whencompared with a simple dipole antenna. Because these antennas weredirectional in nature, certain difficulties arose since they would onlypick up signals from the direction in which the antenna was oriented. Inan attempt to overcome these difficulties, omni-directional antennashave been developed.

SUMMARY OF THE INVENTION The general purpose of this invention is toprovide an improved, omni-directional antenna which provides a greatersignal to noise ratio then previous omnidirectional antennas and is lessexpensive to manufacture or fabricate. To attain this, the presentinvention contemplates a unique arrangement wherein all conductiveelements of the antenna are constructed from a flexible conductivematerial which is laminated to a flexible strip of non-conductivematerial such as mylar. The conductive elements which are laminated tothe mylar material are arranged in a preselected pattern and, in thepreferred embodiment, comprise 11 uniform strips of flexible copper foilwhich are placed adjacent to each other in parallel arrangement and apreselected number of these strips are then electrically connectedtogether by a suitable connecting means. The laminated structure is thenattached to the interior of a rigid non-conductive housing in a circulararrangement, thereby forming the omni-directional antenna.

Therefore, an object of the present invention is to provide an improved,omni-directional antenna which is capable of 360 reception and whichprovides a high signal to low noise ratio.

Another object is to provide an omni-directional antenna which utilizesflexible active elements.

A further object of the invention is to provide an omni-directionalantenna which is impervious to metallically corrosive elements.

Still another object is to provide an omni-directional antenna which isextremely simple and inexpensive to fabricate and at the same time easyto install and main"- tain.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood withreference to the following detailed description when considered inconnection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of aflexible antenna segment which constitutes a preferred embodiment of theinvention.

FIG. 2 is a section of the flexible antenna segment taken on the lines2-2 of FIG. 1.

FIG. 5 is an exploded view of a flexible antenna segment of FIG. 1 incombination with a rigid housing.

FIG. 6 is a perspective view, with a portion removed,

of an alternative housing which may be used in combination with theflexible antenna segment of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawingswherein like reference characters designate like or corresponding partsthroughout the several views, there is shown in FIG. 1 a flexibleantenna segment 10. Referring now to FIGS. 1, 2 and 3, it can be seenthat the flexible antenna segment 10 is a laminated structure comprisinga flexible non-conductive layer 12 and a flexible layer of conductivematerial 14. The layer of flexible conductive material 14 comprises aplurality of strips of flexible conductive material 16 which arearranged in a preselected pattern on the flexible non-conductive layer12 and, as will be explained below, the strips of flexible conductivematerial 16 are permanently affixed to the flexible non-conductive layer12. In the preferred embodiment, eleven strips of flexible conductivematerial are arranged so as to be parallel to each other and spacedapart an equal distance from each other, thereby forming eleven parallelspaced apart strips of flexible conductive material 16a through 16k.

The flexible antenna segment 10 is of preselected length having a firstend 17 and a second end 19. In the preferred embodiment, its length ininches is equal to one quarter wave length of channel 2 or 64 A inches.

As can be seen in FIG. 1, a conductor 18 electrically connects to eachother four of the strips of flexible conductive material, while theremaining seven strips of flexible conductive material 16 areelectrically connected together by a conductor 20. In addition, thestrip of flexible conductive material 16a is segmented at its center byan aperture 22, thus forming two individual flexible conducted strips 24and 26. The flexible conductive strip 26 is electrically connected tothe conductor' 20 while the flexible conductive strip 24 is electricallyconnected to the strip of flexible conductive material 16b by anotherconductor 28. Lastly, as best shown in FIGS. 1 and 2, a conventionalantenna lead 30 is connected to the flexible antenna segment 10 by anysuitable fastening means. In the preferred embodiment, a pair of snapfasteners 46 and 48 are employed. The antenna lead 30 may beconventional twin lead wire wherein the first lead wire 30a iselectrically connected to the conductor 18 while the second lead wire30b is electrically connected to the conductor 20. In this manner, alleleven of the strips of flexible conductive material through 16k areelectrically connected to the antenna lead 30. The antenna lead 30 maythen be utilized to connect the flexible antenna segment 10 to autilization device such as a television set or other similar device.

Referring now to FIG. 4, the method of fabricating the flexible antennasegment 10 will be described. To manufacture the flexible antennasegment 10, any conventional roll feeding machine that is adapted tofeed rolls of continuous material to a receiving station may beutilized. In this regard, a roll 32 of flexible nonconductive material12 is mounted on a feed roller means 33 and is fed to a receivingstation 34. The flexible non-conductive material is treated with a heatresealable polyester adhesive. This heat resealable polyester adhesivemay be applied to the flexible nonconductive material 12 as it istraveling to the receiving station 34 by any suitable means or the roll32 of the flexible non-conductive material 12 may already have beentreated by the manufacturer of the flexible nonconductive material witha heat resealable polyester adhesive. One such material which may bereadily purchased and which contains the heat resealable polyesteradhesive is Mylar and is manufactured by E. I. Du- Pont. In thepreferred embodiment, the Mylar has a thickness of two mils and theadhesive contained on the surface of the Mylar has a thickness of l ,6mils. The width of the roll 32 is designed so as to be the same width asthe desired width of the flexible antenna segment 10. In the preferredembodiment, the roll 32 has a width of seven inches.

Continuous lengths of flexible conductive material 16 are also fed tothe receiving station 34. These continuous lengths of flexibleconductive material 16 are fed from a plurality of rolls 36 ofpreselected width which are mounted on a feed roller means 37. As can beseen in FIG. 2, the roll 36 of flexible conductive material 16 arelocated directly above the roll 32 of flexible nonconductive material 12and as the flexible conductive material 16 is fed towards the receivingstation 34, they are superposed above the flexible nonconductivematerial 12. As mentioned previously with reference to FIG. 1, theflexible antenna segment comprises in the preferred embodiment, elevenstrips of flexible conductive material 16a through 16k. Therefore, it isnecessary to utilize l 1 rolls 36 of flexible conductive material 16. Itwill be recognized, however, that if it is desired to utilize fewer thaneleven strips, then fewer rolls 36 will be required and, likewise, if agreater number of strips were desired, then a greater number of rolls 36will be required.

Each of the rolls 36 are then fed through an alignment apparatus 38. Thealignment apparatus 38 insures that each of the flexible strips 16 aremaintained at a preselected spaced distance from each other. The desiredspacing may be determined empirically and, in the preferred embodiment,it is desired to maintain a spacing of 0. l 25 inches between thestrips. Each of the strips of flexible conductive material 16 in theproposed embodiment are each one-half inch wide and the rolls 36 of thiswidth may be obtained by slitting a larger roll of flexible conductivematerial into individual rolls one-half inch wide. In the preferredembodiment, the flexible conductive material 16 comprises a soft rolledcopper foil which may be purchased commercially from many sources.

The plurality of strips of flexible conductive material 16 and the stripof flexible non-conductive material 12 are continuously fed to thereceiving station 34. At the receiving station 34, each of the strips offlexible conductive material 16 are bonded or affixed to the uppersurface 13 of the flexible non-conductive material 12. As describedabove, the upper surface 13 of the flexible non-conductive layer 12 hasbeen treated with the heat resealable polyester adhesive. At thereceiving station 34, a conventional set of hot rollers applies bothpressure and heat to each of the strips of flexible conductive material16, thereby sealing or affixing each of the flexible conductive strips16 to the upper surface 13 of the flexible non-conductive material 12,thereby forming a continuous laminated flexible conductive material 40.The continuous laminated flexible material 40 may then be formed into aroll 42.

After obtaining the roll 42 of the continuous laminated flexiblematerial 40, the flexible antenna segment 10 may be manufactured bymerely cutting the continuous laminated flexible material 40 intosegments 10 of proper length. In the preferred embodiment, the flexibleantenna segments 10 are cut to a length of 64 1% inches. 64 1% inchesrepresents one quarter wave length, in inches, of television channel 2.After obtaining this proper length, it is then necessary to electricallyconnect together a preselected plurality of the adjacent flexibleconductors 16. As mentioned previously in connection with FIGS. 1through 3, the strips of flexible conductive material 16a, 16b, 16c,16d, 16e, 16f, and 16g are electrically connected together by aconductor 20. In the preferred embodiment, the conductor 20 may comprisea copper conductor which is welded to the layer of flexiblenon-conductive material 12 and to the strips of flexible conductive 16athrough 16g. Similarly, the strips of flexible conductive material 16hthrough 16k are also electrically connected in the similar manner by theconductor 18. As also mentioned previously, the segment 24 of theflexible conductor 16a is electrically connected by a conductor 28 tothe strip of flexible conductive material 16b. As can clearly be seen inFIG. 3, this connection is only made on the upper surface 13 of theflexible non-conductive layer 12. However, if it is desired, a two-sidedconnection may be utilized.

The segments 24 and 26 are shown to be of equal length in the preferredembodiment. To accomplish this, the aperture 22 is placed exactly in thecenter of the strip of flexible conductive material 16a. Thispositioning was determined empirically and it has been found that thebest reception is obtained when the aperture 22 is positioned a gooddistance from each end of the strip of flexible conductive material 16a.However, other placements may be utilized.

As mentioned previously, the antenna lead 30 is electrically connectedto the conductors l8 and 20 by any suitable fastening means. In thepreferred embodiment, the snap fasteners 46 and 48 are inserted into theflexible, non-conductive layer 12 and the flexible conductive layer 14,as well as contacting each of the conductors 20 and 18, as shown inFIGS. 1 and 2. The snap fasteners 46 and 48 are identical. The snapfastener 46 comprises a male portion 45 and a female portion 47. Theupper part 45a male portion 45 is in electrical contact with theconductor 18 while the female portion 47 is in electrical contact withthe antenna lead 30a or 30b. By utilizing snap fasteners 46 and 48, avery secure, as well as inexpensive, fastening of the antenna lead 30may be accomplished.

After fabricating the flexible antenna segment 10, this antenna segmentmay then be coated with a protective non-conducting coating. Anysuitable protective coating, such as plastic, may be utilized. If it isdesired, rather than utilizing plastic coating, a secodn layer of Mylarcan be placed over the layer of flexible conductive material 16, therebyforming a three-layer flexible antenna segment having the layer offlexible conductive material 16 sandwiched in between two layers offlexible non-conductive Mylar 12.

After fabricating the flexible antenna segment 10, as described above,the flexible antenna segment is then affixed or bonded to a rigidhousing. In the preferred embodiment, it is desired to make the antennaomni-directional and, therefore, the housing must be circularly shaped.Referring now to FIG. 5, a preferred housing 50 is shown. The housing 50comprises an upper segment 52 and a lower segment 54. The upper segment52 is generally circularly shaped and has a circular rim 56 from whichdownwardly protrudes a cylindrically shaped extension 58. The dimensionsof the cylindrically shaped extension are such that the flexible antennasegment 10 is wrapped around the outer surface 60 of the cylindricallyshaped extension 58. When wrapped in this manner, and affixed or bondedto the housing, a space is formed between the first end 17 and thesecond end 19 of the flexible antenna segment 10. The flexible antennasegment 10 may be bonded to the rigid housing by any suitable means suchas a cementor by heat. After the flexible antenna segment 10 has beenaffixed to the downwardly protruding cylindrically shaped extension 58,the lower segment 54 of the housing 50 is again mated with the uppersegment. As can be seen in FIG. 5, the upper segment acts as a malemember and the lower segment 54 acts as a female member thereby forminga compact circular donut-shaped housing wherein the flexible antennasegment 10 is completely protected from any corrosive elements. Formounting purposes, a support bar 62 may then be placed across theopening in the housing 50 and a shaft (not shown) may then be connectedto the support 62 to mount the antenna in a conventional manner.

Referring now to FIG. 6, an alternative housing 70 is disclosed. Thehousing 70 is generally shaped in the form of a hemisphere. The upperportion 72 of the hemisphere, however, comprises a vertically shapedsegment 74 which is adapted to receive the flexible antenna segment 10.The width of this vertically shaped segment 74 is made slightly greaterthan the width of the flexible antenna segment 19 and, in the preferredembodiment, is 7 V4 inches tall. The circumference of the housing 70 isslightly larger than the length of the flexible antenna segment 10. Ascan be seen in FIG. 6, the flexible antenna segment 10 is bonded orattached to the interior surface of the vertical segment 74. After theflexible antenna segment 10 has been affixed in this manner, a cover(not shown) may be affixed to the lower open end of the housing 70,thereby closing the housing and thereby making the antenna completelyimpervious to corrosive elements. a

It will be recognized by one skilled in the art that it is immaterial tothe practice of this invention whether housing 50 is utilized or housing70 is utilized and, fur thermore, any otehr similar housing may beemployed without departing from the spirit and the scope of theinvention.

As shown in FIG. 1, the preferred embodiment utilizes eleven strips offlexible conductive material connected together in several groups. Theactual connections and dimensiosn of this antenna have been foundempirically and provide the best television reception over channels 2through 13 as well as the UHF channels. The dimensions of this antennaare provided below; however, it is to be recognized that thesedimensions are merely illustrative of the invention, and variousmodifications may be made without departing from the spirit and thescope of the invention. The flexible non-conductive material utilized inthe preferred embodiment is mylar an it two mills thick. An adhesivecoating l k mills thick is applied to one surface of the mylar. Theflexible conductive material utilized is rolled copper foil which is0.0014 inches thick and is k inch wide. The purity of the copper isrolled 99.9 percent. The resistivity of one ounce of this copper is0.15940 ohm-gram meter at 20 centigrade. The tensile strength is equalto 50. The connectors 18 and 20 are manufactured from a copper alloy andare one inch wide. The strips of flexible conductive material 16 areaffixed to the mylar at the receiving station 34. The receiving station34 applies a pressure of 30 psi at 325 F. to each of the strips offlexible conductive material 16 thereby bonding the strips of flexibleconductive material 16 to the flexible non-conductive layer 12. Thespace between each adjacent strip of flexible conductive material 16 isapproximately 0.125 inches.

While specific dimensions and components have been described, it will berecognized that these dimensions and components are only exemplary andthat if the antenna were to be used with other frequencies than thetelevision frequency, different lengths and different spacings may beutilized and obviously, many modifications and alterations may be madeherein without departing from the spirit and the scope of the inventionas set forth in the appended claims.

What is claimed is:

1. An omni-directional television receiving antenna comprising:

a layer of flexible non-conductive material;

a plurality of parallel strips of flexible conductive material having apreselected substantially equal length wherein each of said-strips offlexible conductive material includes a first end and a second end andwherein each of said strips of flexible conductive material are affixedto said layer of flexible non-conductive material;

first means for electrically connecting said strips of flexibleconductive material to a utilization device; and

a rigid non-conductive circular housing wherein said layer of flexiblenon-conductive material is affixed to the interior of said housingwhereby said first end of each of said conductive strips is placedadjacent to its respective second end of said conductive strips therebyforming a plurality of substantially circularly shaped conductiveelements.

2. The omni-directional antenna of claim 1 further comprising:

second means for electrically connecting a preselected number of saidparallel conductive strips to each other.

3. The omni-directional antenna of claim 2 wherein said second meanscomprises a strip of conductive material affixed to said first ends ofeach of said preselected parallel conductive strips.

4. The omni-directional antenna of claim 1 wherein said antennacomprises 11 parallel strips of flexible conductive material affixed tosaid non-conductive material.

5. The omni-directional antenna of claim 4 further comprising:

second means for electrically connecting together the first ends of fourof said conducting strips thereby forming a first group of conductiveelements', and

third means for electrically connecting together the first ends of theremaining seven of said conducting strips thereby forming a second groupof conductive elements.

6. The omni-directional antenna of claim further comprising:

a means for electrically bisecting one of said strips of conductivematerial of said second group of conductive elements whereby one of saidbisected segments remains electrically connected to said third means;and

fourth means for electrically connecting the other of said bisectedsegments to another of said strips of conductive material in said secondgroup of conductive elements.

7. The omni-directional antenna of claim 6 wherein said flexiblenon-conductive material comprises mylar and wherein said flexible stripsof conductive material each comprise copper foil.

8. The omni-directional antenna of claim 7 wherein said circular housingcompletely encloses said layer of flexible non-conductive materialthereby making said antenna impervious to corrosive elements.

9. The omni-directional antenna of claim 8 wherein said first meanscomprises a twin lead wire and wherein one of said leads is electricallyconnected to said first group of conductive elements and wherein theother of said leads is electrically connected to said second group ofconductive elements.

10. The omni-directional antenna of claim 9 wherein each of said leadsare electrically connected to said conductive elements by a snapfastening means.

1 l. The omni-directional antenna of claim 3 wherein said first means iselectrically connected to said strips of flexible conductive material bya snap fastening means.

1. An omni-directional television receiving antenna comprising: a layerof flexible non-conductive material; a plurality of parallel strips offlexible conductive material having a preselected substantially equallength wherein each of said strips of flexible conductive materialincludes a first end and a second end and wherein each of said strips offlexible conductive material are affixed to said layer of flexiblenon-conductive material; first means for electrically connecting saidstrips of flexible conductive material to a utilization device; and arigid non-conductive circular housing wherein said layer of flexiblenon-conductive material is affixed to the interior of said housingwhereby said first end of each of said conductive strips is placedadjacent to its respective second end of said conductive strips therebyforming a plurality of substantially circularly shaped conductiveelements.
 2. The omni-directional antenna of claim 1 further comprising:second means for electrically connecting a preselected number of saidparallel conductive strips to each other.
 3. The omni-directionalantenna of claim 2 wherein said second means comprises a strip ofconductive material affixed to said first ends of each of saidpreselected parallel conductive strips.
 4. The omni-directional antennaof claim 1 wherein said antenna comprises 11 parallel strips of flexibleconductive material affixed to said non-conductive material.
 5. Theomni-directional antenna of claim 4 further comprising: second means forelectrically connecting together the first ends of four of saidconducting strips thereby forming a first group of conductive elements;and third means for electrically connecting together the first ends ofthe remaining seven of said conducting strips thereby forming a secondgroup of conductive elements.
 6. The omni-directional antenna of claim 5further comprising: a means for electrically bisecting one of saidstrips of conductive material of said second group of conductiveelements whereby one of said bisected segments remains electricallyconnected to said third means; and fourth means for electricallyconnecting the other of said bisected segments to another of said stripsof conductive material in said second group of conductive elements. 7.The omni-directional antenna of claim 6 wherein said flexiblenon-conductive material comprises mylar and wherein said flexible stripsof conductive material each comprise copper foil.
 8. Theomni-directional antenna of claim 7 wherein said circular housingcompletely encloses said layer of flexible non-conductive materialthereby making said antenna impervious to corrosive elements.
 9. Theomni-directional antenna of claim 8 wherein said first means comprises atwin lead wire and wherein one of said leads is electrically connectedto said first group of conductive elements and wherein the other of saidleads is electrically connected to said second group of conductiveelements.
 10. The omni-directional antenna of claim 9 wherein each ofsaid leads are electrically connected to said conductive elements by asnap fastening means.
 11. The omni-directional antenna of claim 3wherein said first means is electrically connected to said strips offlexible conductive material by a snap fastening means.